$ sudo apt-get update
$ sudo apt-get install libjmagick6-jni 

libjmagick6-jni is installed in your system.

Make ensure the libjmagick6-jni package were installed using the commands given below,

$ sudo dpkg-query -l | grep libjmagick6-jni *

You will get with libjmagick6-jni package name, version, architecture and description in a table

libjmagick6-jni package basic information: